None.
The present invention relates generally to the field of window coverings and more particularly to a tensioner for a tension shade/blind. (hereinafter referred to as a (tension shadexe2x80x9d). Window coverings typically include a headrail and a bottom rail movable toward and away from the headrail. A window covering material such as a pleated blind or a plurality of slats hang from the headrail and are operatively connected to the bottom rail. In the case of a pleated blind, a pleated material hangs from the headrail and is attached to the bottom rail. As the bottom rail is raised toward the headrail the pleated material accumulates on the bottom rail. In a traditional pleated blind, a lift cord is secured to the bottom rail and extends upward through the pleated material, into the headrail and through a cord lock. The bottom rail and pleated material are raised and lowered by pulling on the free end of the lift cord. In a venetian blind with slats, at least two ladders supporting the slats extend from the headrail and are operatively connected to the bottom rail. A lift cord connected to the bottom rail extends through the slats and headrail and is releasably secured in a cord lock.
In a tension shade the lift cord is replaced with tension cords that are connected to and extend from the headrail through the pleated material or slats, through the bottom rail and are secured under tension to a window frame or structure. The tension on the tension cords fix the location of the bottom rail relative to the headrail. The bottom rail is moved toward and away by a user simply pulling or pushing the bottom rail to the desired location. In order to maintain sufficient tension on the tension cords, a spring is often used in either the headrail or bottom rail, or located on the window sill or structure.
Once the tension is set and the blind is installed, the cords tend to give over a period of time and lose tension. If a spring is used, the spring can be overloaded during installation to ensure that there will be sufficient tension in the tension cords over the life of the blind.
Tension shades that are used in recreational vehicles are subject to more vibrations and movement then tension shades used in a fixed structure. As a result of the increased vibration and movement, the tension shades are more likely to lose tension over time. Accordingly, it is important to set the tension to the proper level upon installation to ensure optimal operation of the blind over time. One difficulty in setting the tension occurs when the tension cords are secured to the window frame or structure.
One such well known fastening device is illustrated in U.S. Pat. No. 6,044,889 in the tension cords 22, 26 are attached to a reel 23. The reel is secured to the wall thereby setting the tension on the tension cords. The tension cords are tied on to the reel like anchor. In order to tighten the tension on the cords the tension cord can be wrapped around the respective reel. (See col. 3 lines 8-15). There are a number of problems with this type of anchor. First, the anchor is typically formed from plastic and subject to breaking at the point at which the tension cord is tied on. When the anchor breaks, the entire shade is often returned to the manufacturer for replacement. Additionally, it is difficult to set the tension to the correct level when installing the anchor, since the cord is already attached with a knot. Additionally, incremental adjustment is achieved by wrapping the tension cord around the reel.
Accordingly, it would be desireable to provide a tensioner for use in a tension window covering that is easy to install and adjust and that is not subject to breaking.
One embodiment of the invention relates to a tension shade comprising a headrail supporting a window covering and a bottom rail operatively connected to the window covering. At least one tension cord extends from the headrail and is operatively connected to the bottom rail. At least one tensioner is connected to the tension cord and is configured to be releasably secured to a structure. The tensioner includes a first component having an engagement surface and a second component having a second engagement surface. The first component is configured to snap fit into the second component. The first and second components have a first position wherein the first engagement surface and the second engagement surface are spaced apart a predetermined distance sufficient to frictionally engage a portion of the tension cord. The first component is movable within the second component from the first position to a second fully engaged position to clamp the tension cord between the first and second engagement surfaces.
Another embodiment includes a tensioner for securing a tension cord of a tension shade attached to a structure. The tensioner includes a lock component having an inner surface, an outer surface and an aperture extending therethrough. A casing includes an inner surface, an outer surface and an aperture extending therethrough, and an outer periphery defining a cavity for receiving the lock therein. The lock and the casing form a first and second opening and a path therebetween for receiving a portion of the tension cord. The opening forms an axis substantially perpendicular to an axis defined by the apertures of the lock and casing. A fastener extends through the apertures of the lock and casing to secure the lock and casing to the structure and to fix the location of the tension cord relative to the casing.
In still another embodiment a method of installing a tension shade to a structure includes providing a tension shade with a headrail, a bottom rail, and a window covering operatively connected the headrail and bottom rail. A pair of tension cords extend from the headrail and are operatively contacting the bottom rail. A tensioner is attached to each respective tension cord with sufficient friction to locate each tensioner an the tension cord and is slidably movable along each respective tension cord with the application of force. A first tensioner is secured to the structure with a fastener and the tensioner is clamped to one of the tension cords with sufficient force prohibiting movement of the tension cord relative to the first tensioner. A second tensioner is attached to the structure with a a second fastener. The other tension cord is moved relative to the second tensioner to provide sufficient tension on the tension cord to maintain the location of the bottom rail to the headrail and any location of the bottom rail between a fully raised position where the bottom rail is proximate the headrail and a fully lowered position where the bottom rail is distal the headrail. Finally, the second tensioner is fully secured to the structure with sufficient force to prohibit movement of the tension cord relative to the first tensioner.